Biomedical subjects

Jung-Eun Lee

Publications and source records attributed to Jung-Eun Lee.

5 recordsLinked to original sources

PubMed2006

Characteristics for the hydration reaction of limestone washing process sludge from steel works.

In order to understand the fundamental features of hydration reaction of sludge generated from a limestone washing process at a steel works and to improve its utilization as a secondary resource, the physicochemical properties of the sludge were examined and its hydration characteristics were investigated under several different conditions. The sludge was mainly composed of CaCO3 and its thermal behavior was observed to be affected by its composition. Compared to the conventional methods for hydrating limestone, using an ultrasonic vibration reactor produced more impalpable slacked lime powder with an even grain size because of the uniform reaction to the entire pulp without a violent reaction. Adequate pulp density for the production of fine slaked lime in an ultrasonic vibration reactor was observed to be 10 wt% or less. Hydration of the sludge formed by the limestone washing process was better and produced more homogeneous fine slacked lime powder than that of natural limestone. Slaked lime powder formed from the limestone washing-based sludge was very minute and the hydration reaction was completed within 10 minutes. In addition, the degree of hydration of the limestone washing-based sludge was found to be higher than that of natural limestone.

Calcium Carbonate↗

PubMed2005

Root functioning modifies seasonal climate.

Hydraulic redistribution (HR), the nocturnal vertical transfer of soil water from moister to drier regions in the soil profile by roots, has now been observed in Amazonian trees. We have incorporated HR into an atmospheric general circulation model (the National Center for Atmospheric Research Community Atmospheric Model Version 2) to estimate its impact on climate over the Amazon and other parts of the globe where plants displaying HR occur. Model results show that photosynthesis and evapotranspiration increase significantly in the Amazon during the dry season when plants are allowed to redistribute soil water. Plants draw water up and deposit it into the surface layers, and this water subsidy sustains transpiration at rates that deep roots alone cannot accomplish. The water used for dry season transpiration is from the deep storage layers in the soil, recharged during the previous wet season. We estimate that HR increases dry season (July to November) transpiration by approximately 40% over the Amazon. Our model also indicates that such an increase in transpiration over the Amazon and other drought-stressed regions affects the seasonal cycles of temperature through changes in latent heat, thereby establishing a direct link between plant root functioning and climate.

Atmosphere↗

PubMed2004

Therapeutic effects of lysophosphatidylcholine in experimental sepsis.

Sepsis represents a major cause of death in intensive care units. Here we show that administration of lysophosphatidylcholine (LPC), an endogenous lysophospholipid, protected mice against lethality after cecal ligation and puncture (CLP) or intraperitoneal injection of Escherichia coli. In vivo treatment with LPC markedly enhanced clearance of intraperitoneal bacteria and blocked CLP-induced deactivation of neutrophils. In vitro, LPC increased bactericidal activity of neutrophils, but not macrophages, by enhancing H(2)O(2) production in neutrophils that ingested E. coli. Incubation with an antibody to the LPC receptor, G2A, inhibited LPC-induced protection from CLP lethality and inhibited the effects of LPC in neutrophils. G2A-specific antibody also blocked the inhibitory effects of LPC on certain actions of lipopolysaccharides (LPS), including lethality and the release of tumor necrosis factor-alpha (TNF-alpha) from neutrophils. These results suggest that LPC can effectively prevent and treat sepsis and microbial infections.

Animals↗

PubMed2004

Age hardening by dendrite growth in a low-gold dental casting alloy.

Commercial low-gold dental casting alloy composed of Ag-Pd-In-Au-Zn was studied to clarify the age-hardening mechanism and related microstructural changes. The hardness of solution-treated specimen began to increase and reached the maximum value with ageing time, and then the maximum hardness value decreased by further ageing. The changes of X-ray diffraction (XRD) pattern during isothermal ageing revealed that the age hardening was not caused by phase transformation. By comparing the age-hardening curve with the changes in full-width at half-maximum of the XRD peaks at each ageing time, it was revealed that the coherency strains were formed in the Ag-rich matrix, which contributed to the hardness increase during ageing. From scanning electron microscopic observation and electron probe microanalysis, it was clarified that fine particle-like structures composed of InPd containing small amount of Zn gathered by diffusion in the Ag-rich matrix, and the coherency strains which formed during that time caused the hardness increase in the early stage of age-hardening process. The coherency strains were released by the progress of coarsening of Zn-containing InPd dendrite during further ageing, which caused the overaging in the later stage of age-hardening process.

Biocompatible Materials↗

PubMed2004

Notes on a discrepancy in mitochondrial DNA and allozyme differentiation in a pond frog Rana nigromaculata.

Analyses of complete 1143-base pair sequence of the mitochondrial cytochrome b gene demonstrated a sister relationship between Japanese R. nigromaculata and Korean R. plancyichosenica, but not with Korean R. nigromaculata, while the allozyme data strongly supported the monophyly of the Korean and Japanese populations of R. nigromaculata. We surmise this discordance to be the result of the inheritance of introduced mtDNA and the dilution of introduced nuclear DNA in mixed lineages after past hybridization and genome introgression between the two species, although the direction of introgression is unknown.

Animals↗